There are many different types of vehicles which are taken off-roading for recreational use. Many of these vehicles have various features to prevent the vehicle from being limited in off-road travel, and increase capability to maneuver through difficult terrain.
Some vehicles are manufactured specifically for the purpose of off-road driving, while some vehicle owners make modifications to their vehicle to improve the vehicle's off-road capability. On some off-road trails, it may difficult to maneuver exceedingly tight turns. The width and accessibility of various off-road trails is often very different when compared to a two-lane road. Some turns and other maneuvers require the use of the reverse gear and one or more forward gears such that the vehicle is moved forward and reverse several times to change the position of the vehicle, and thereby allowing the vehicle to continue onward through the trail. Many off-road enthusiasts do not prefer to maneuver through trails in this manner, but prefer to have a vehicle with increased maneuverability. To avoid changing between the forward gears and the reverse gear several times when performing a turning maneuver, some owners of off-road vehicles modify their vehicles such that the vehicle may turn and change position without the use of the reverse gear, essentially performing a maneuver referred to as a “front dig.” If the proper modifications are made, the vehicle is able to perform a front dig, and is not required to use the reverse gear to complete the turn. A front dig maneuver involves the driver disconnecting the rear axle output at the transfer case, either through the use of pneumatics, or mechanically. The driver of the vehicle then applies the brakes such that braking pressure is applied to the rear axle only, the vehicle is steered in the desired direction, and the driver then applies the accelerator pedal. With the rear axle disconnected, all of the output of the engine is sent to the front axle, which causes the front wheels to rotate and pull the vehicle in the desired direction. With brake pressure applied to the rear wheels only, the rear wheels do not roll, and the vehicle pivots about the rear axle. This allows the driver to perform extremely tight turns without the use of the reverse gear in the transmission.
With current production vehicles, modifications to the transfer case and brakes are needed to enable the vehicle to complete a front dig maneuver. The transfer case splits the output of the engine between the front axle and rear axle. Some transfer cases have the ability to disconnect output to either the front axle or rear axle using a selection lever located in the interior of the vehicle. If the transfer case of the vehicle does not have this capability, it is common for an additional tail housing to be installed between the transfer case and the rear differential. The additional tail housing may be equipped with a selection lever, or utilize air pressure to disconnect the rear output, allowing for control of the distribution of power to the front wheels or rear wheels.
The needed modification to the braking system involves replacing the stock brake master cylinder with twin master cylinders, and replacing the pedal assembly with two brake pedals. When the twin master cylinders are used, one master cylinder is plumbed to the rear axle brakes and the other master cylinder is plumbed to the front brakes. The EBS also includes a pump, valves, and an electronic controller. The EBS is connected to each brake via brake lines. At any time, the EBS controls the valves to maintain, dump, or build pressure at any wheel.
However, incorporating these types of modifications into a vehicle may also alter or change the drivability of the vehicle in a negative manner.
Accordingly, there exists a need for a system that is incorporated into a vehicle during the manufacturing process, which allows the vehicle to perform a dig maneuver, without sacrificing vehicle drivability.